1. Field of the Invention
The present invention relates to a method and system for fitting work-pieces of complicated shapes.
Definition:
The term work-pieces means parts to be fitted with each other for constructing various products, such as a heater unit, cooler unit, and a booster (blower) unit for an air conditioning device for an automobile, a hand scanner, a personal computer, cases for storing various products, such as dolls and toys, cases for storing clothes and shoes, and cases for storing foods or miscellaneous goods, parts for furniture, intermediate parts, parts for constructing a building, and parts for an enclosure, and so on. The work-piece may be advantageously made as a molded product from a resilient or flexible material such as a plastic or as a shaped product from a thin web material such as tinplate and zinc sheet, or as a shaped product from a thick paper plate, such as a corrugated cardboard. These work-pieces may have various shapes such as a cube, a rectangular parallelepiped, a polygonal pillar shape, or a cylindrical body with or without interrupted portions.
The term "fitting land" indicates a separated section in a work-piece which is separated from the remaining section (s) thereof and which is subjected to a separate fitting operation with a corresponding section in an opposite work-piece.
The term "fitting portion" indicates a location in a fitting land which is fitted to a paired fitting portion in a fitting land in an opposite work-piece. Such a pair of fitting lands includes a combination of projection and a groove (FIG. 13), a combination of a pin and a hole (FIG. 30), or a combination of recessed surfaces (FIG. 33).
The term "low rigidity portion" indicates a portion among the portions in a fitting land, which provides a relatively lower value of the rigidity, i.e., of higher value of elasticity. As will be apparent from the disclosure hereinbelow, rigidity as used herein relates to stiffness or stiffness co-efficient which is the ratio of the force acting on a land to the displacement of the land.
The term "provisional fitting state" indicates a state where a fitting land in a work-piece is partially engaged with a portion in the opposite fitting work-piece, so that relative movement between work-pieces is easily allowed by an elasticity thereof, while the partially fitted condition is maintained.
The term "relative deviation" indicates the distance of a portion of a fitting land from a corresponding portion of the opposite fitting land, these fitting lands being fitted with each other.
The term "assembling allowance" means that a relative deviation between fitting lands is within a range which allows these fitting lands to be engaged with each other due to a guiding operation.
The term "self-guided fitting" is a fitting operation of a pair of fitting lands in work-pieces caused by a relative rotation of the work-pieces, which fitting operation is commenced from a location of the lands as being fitted, as an origin, and which is gradually proceeded under a self guiding action of the fitting lands, as they are being fitted.
2. Description of a Related Art
A product such as an air conditioning device for an automobile is basically constructed from separated parts which are fitted with each other. In this kind of product, a plurality of fitting lands is provided, which makes it difficult for the fitting operation to be easily and reliably executed. Namely, in order to obtain a desired fitting operation, a desired relationship should be maintained between the separated parts in every fitting land. In the prior art, a plurality of supporting members are provided for obtaining a desired relationship between the separated parts in every fitting lands. However, this requires a use of a large number of supporting members, causing the device to be complicated and the fitting process to be troublesome.